The present invention broadly relates to circuit breakers or interrupters and pertains, more specifically, to a new and improved method of assembling a circuit-breaker pole for a medium-voltage or high-voltage circuit breaker. The present invention also relates to a new and improved apparatus for carrying out or performing the inventive method as well as to a new and improved circuit-breaker pole for a medium-voltage or high-voltage circuit breaker.
Generally speaking, the method of the present invention is of the type according to which a support insulator, through which an insulating drive rod piercingly extends, is mechanically fixedly connected at one end thereof with a mechanism housing, into which there is sealingly introduced a drive element connected to the insulating drive rod, and at the other end thereof with an electrically conductive intermediate part supporting a lower terminal and electrically connected with a movable contact piece coupled to the insulating drive rod, and according to which a quenching-chamber insulator is mechanically fixedly connected at one end thereof with the intermediate part, and at the other end thereof with a top or upper housing supporting an upper terminal and a stationary contact piece co-acting with the aforesaid movable contact piece. Fittings or mounting parts are provided for the connections of the support insulator with the mechanism housing and the intermediate part, respectively, and for the connections of the quenching-chamber insulator with the intermediate part and the top housing, respectively, whereby the mechanism housing, the intermediate part and the top housing constitute the pole components for assembly with the insulators. These fittings or mounting parts are connected in each case, on the one hand, with the respective insulator by feeding casting material into a ring-shaped space between the respective insulator and the fitting or mounting part and, on the other hand, with the respective pole component.
A gas-blast insulated circuit-breaker pole of a high-voltage circuit breaker and assembled according to a prior art method of this type is disclosed, for example, in SPRECHER ENERGIE Catalog 42.B.4 "SF.sub.6 -Leistungsschalter", published in September, 1990 by the assignee of the instant application. Prior to pole assembly of this circuit breaker known to the art, a tubular support or post insulator and a likewise tubular quenching-chamber insulator, which are open in the axial direction, are provided with respective metal fittings or mounting parts which surround or encompass at a distance the axial end regions of the two insulators. To connect the fittings with the respective insulators, the spaces between these metal fittings and the respective insulators are filled with casting material such as, for example, Portland cement. In the course of pole assembly, the tubular support or post insulator is placed upon a mechanism housing, whereby an annular seal is previously laid on a sealing surface or face of the mechanism housing, so that the lower end face of the support insulator comes to bear upon this annular seal. The support insulator is then fixedly mounted at the mechanism housing by means of a set of screw connections supported at the lower metal fitting and at the mechanism housing. An insulating drive rod piercingly extends through the support insulator in the axial direction and the lower end thereof is connected by means of a lever-bracket gear with a drive shaft which is sealingly introduced into the mechanism housing and rotatably mounted at the latter. An intermediate part provided with a lower terminal is placed or positioned upon the support insulator after having laid a likewise annular seal therebetween. Prior thereto, there is mounted at this intermediate part a movable contact piece together with a compression system for producing the flow of quenching gas, the movable contact piece having to be connected to the insulating drive rod. The tubular quenching-chamber insulator is then put over the compression system and the movable contact piece and mounted at the tubular support or post insulator by means of a second set of screw connections which piercingly extend through the intermediate part and are supported at the upper metal fitting of the support insulator and at the lower metal fitting of the quenching-chamber insulator. A top or upper housing is deposited on the quenching-chamber insulator after having laid an annular seal therebetween, the top housing carrying a stationary contact piece co-acting with the movable contact piece. This top housing is fixedly mounted at the upper metal fitting of the quenching-chamber insulator by means of a third set of screw connections. An upper terminal of the circuit-breaker pole is provided at the top housing. Having thus completed the assembly of the circuit-breaker pole, a leak test can be now carried out.
In order to ensure that the movable contact piece is accurately aligned with the stationary contact piece, the quenching-chamber insulator with the metal fittings mounted thereat is precisely measured in a gage prior to assembly and mounting. Furthermore, checking holes are drilled into the respective metal fittings, through which alignment pins are inserted during assembly, these alignment pins being also plugged into analogous checking holes provided at the top or upper housing and the intermediate part, respectively.
It is readily conceivable that this known method of assembling and mounting a circuit-breaker pole represents a relatively time-consuming operation and requires extensive preparatory work and a corresponding expenditure for auxiliary devices. In case the result of the leak test is negative, there is no alternative but to dismount or dismantle the completed or finished circuit-breaker pole.